Fiber composite for application of a liquid

ABSTRACT

Provided is a fiber composite for the application of a liquid, including a fibrous member containing a porous carbon material having a specific surface area value by the nitrogen BET method of 10 m 2 /g or more, and a pore volume by the BJH method of 0.2 cm 3 /g or more.

BACKGROUND

The present disclosure relates to a fiber composite for the application of a liquid.

In recent years, attention is drawn to water showing reduction properties, such as alkaline ion water, electrolytic reduced water and hydrogen water, from the standpoint of the maintenance of good health (see, for example, Japanese Unexamined Patent Application Publication Nos. 2003-301288, 2002-348208 and 2001-314877.) Also, Medical Associations have proved in recent years that oxidative stress substances including an oxygen-based radical which is referred as active oxygen in a broad sense such as a superoxide radical, a hydroxyl radical, hydrogen peroxide, singlet oxygen, nitric monoxide and lipid peroxide forms a factor of various diseases and aging. It is said that making antioxidative cosmetics act on a skin and removing these oxidative stress substances are very effective to prevent various diseases and aging.

SUMMARY

So far as the present inventors know, simple ways and means for adding some properties such as antioxidative properties to liquid cosmetics is not yet known.

Thus, it is desirable to provide a fiber composite for the application of a liquid that provides a liquid (for example, a skin lotion) with antioxidative properties, conveniently when a user uses it.

According to a first embodiment of the present disclosure, there is provided a fiber composite for the application of a liquid, including a fibrous member containing a porous carbon material having a specific surface area value as measured by the nitrogen BET method of 10 m²/g or more, and a pore volume as measured by the BJH method of 0.2 cm³/g or more, desirably 0.4 cm³/g or more.

According to a second embodiment of the present disclosure, there is provided a fiber composite for the application of a liquid, including a fibrous member containing a porous carbon material having a specific surface area value as measured by the nitrogen BET method of 10 m²/g or more, and a total pore volume determined by the Non Localized Density Functional Theory of 0.5 cm³/g or more, desirably 1.0 cm³/g or more, of which the pores have diameters in the range from 1×10⁻⁹ m to 5×10⁻⁷ m.

According to a third embodiment of the present disclosure, there is provided a fiber composite for the application of a liquid, including a fibrous member containing a porous carbon material having a specific surface area value of 10 m²/g or more as measured by the nitrogen BET method, and at least one peak in a pore diameter distribution determined by the Non Localized Density Functional Theory in the range from 3 nm to 20 nm. A ratio of the total volume of the pores each having a pore diameter in the range from 3 nm to 20 nm, is 0.2 or more of the total pore volume.

According to the first to third embodiments of the present disclosure, the fiber composite for the application of a liquid can easily provide the liquid (for example, a skin lotion or the like) with the antioxidative properties such that the oxidative stress substances contained in the liquid are removed with certainty, and the oxidation-reduction potential of the liquid is decreased with certainty. This is accomplished by specifying the specific surface area as measured by the nitrogen BET method, the pore volume, and the pore distribution of the porous carbon material. In addition, the fiber composite may be used by wetting the fibrous member with the liquid (for example, a skin lotion or the like). Thus, the liquid can be provided with the properties including the antioxidative properties by a very simple ways and means. In general, the oxidative stress substances easily receive electrons (in other words, the standard oxidation-reduction potential is high in a positive direction). Therefore, when the oxidative stress substances are removed, the ease of electron receiving is decreased (the ease of electron giving is increased). In other words, the oxidation-reduction potential gets higher in a negative direction.

These and other objects, features and advantages of the present disclosure will become more apparent in light of the following detailed description of best mode embodiments thereof, as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a graph showing the relation between the adding amount of the porous carbon material according to Example 1/active carbon according to Comparative Example 1 and the pH;

FIG. 2 is a graph showing the relation between the adding amount of the porous carbon material according to Example 1/active carbon according to Comparative Example 1 and the oxidation-reduction potential.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the embodiments, and various numerical values and materials mentioned in the description of the embodiments are merely examples. The embodiments will be described in the following order.

1. Fiber composite for the application of a liquid according to the first to third embodiments of the present disclosure, general description

2. Example 1 (the fiber composite for the application of a liquid according to the first to third embodiments of the present disclosure), and other

[Fiber Composite for the Application of a Liquid According To the first to third embodiments of the present disclosure, General Description]

In the fiber composite for the application of a liquid according to the first to third embodiments of the present disclosure, the porous carbon material can have a form where a functional material attached thereto. Such form may be called “a porous carbon material composite” as a matter of convenience.

In the fiber composite for the application of a liquid according to the first to third embodiments of the present disclosure including the above-described desirable form, when the fibrous member is impregnated with the liquid, the form which is to apply the liquid (use form) can be provided. In the use form, when the liquid is contacted with the porous carbon material, the oxidative stress substances contained in the liquid can be removed, or when the liquid is contacted with the porous carbon material, the oxidation-reduction potential of the liquid can be decreased. In other words, the liquid can be provided with the properties such as the antioxidative properties.

Example of the liquid can be water, but is not limited thereto. For example, a skin lotion, a skin milk, and a cleansing product of removing stains as sweat, oils and fats, a lipstick or the like can be cited.

Examples of the oxidative stress substances can be a hydroxyl radical, singlet oxygen, a superoxide radical, hydrogen peroxide, nitric monoxide, lipid peroxide or the like. Removing the oxidative stress substances contained in the liquid means that the state where the oxidative stress substances (a hydroxyl radical, singlet oxygen, a superoxide radical, hydrogen peroxide, nitric monoxide and lipid peroxide, all of which are active oxygen species) exist is changed to the state where the oxidative stress substances are reduced by the porous carbon material and the oxidative stress substances are changed to water molecules or oxygen molecules.

Also, the oxidation-reduction potential of the liquid is decreased. When the oxidation state where chlorine, trihalomethane and the oxidative stress substances (a hydroxyl radical, singlet oxygen, a superoxide radical, hydrogen peroxide, nitric monoxide and lipid peroxide, all of which are active oxygen species) are contained is changed, by the removal of those substances, to the state where mineral components (which is considered as remaining ash contents contained on/in the porous carbon material, which are produced during firing and activation) are eluted, the oxidation-reduction potential of the liquid is thus decreased. In other words, it is considered that since chlorine, trihalomethane and the oxidative stress substances have a high positive oxidation-reduction potential (i.e., have a high degree of acidity), absorption by the porous carbon material, removal by the oxidation-reduction reaction, and the elution of a strong alkali/weak acid salt (such as potassium carbonate) contribute to the decrease of the oxidation-reduction potential. The oxidation-reduction potential of the liquid can be measured by using an electrometer having three electrodes including an Ag/AgCl electrode as a reference electrode. It is desirable that the decreased oxidation-reduction potential be 150 millivolts or less.

In the fiber composite for the application of a liquid according to the first to third embodiments of the present disclosure including the above-described desirable form, one of the raw materials in the porous carbon material is desirably a plant-based material containing silicon (Si). In this case, it is not especially limited, but one of the raw materials of the porous carbon material is the plant-based material containing 5% by mass or more of silicon (Si), and the porous carbon material contains 5% by mass or less of silicon (Si), desirably 3% by mass or of less silicon (Si), and more desirably 1% by mass or less of silicon (Si).

In some cases, a hydrophilic treatment or a hydrophobic treatment may be applied to the surface of the porous carbon material (hereinafter collectively referred to as “the porous carbon material according to the present disclosure, etc.”) or the porous carbon material composite forming the fiber composite for the application of a liquid (hereinafter collectively referred to as “the fiber composite for the application of a liquid according to the present disclosure, etc.”) according to the first to third embodiments of the present disclosure including the above-described desirable form.

In the fiber composite for the application of a liquid according to the present disclosure, etc., due to the fact that a small amount of a carbonate produced in carbonization and activation steps is eluted from the porous carbon material according to the present disclosure, etc., for example, and an ash content is increased by an increase of the degree of activation in the porous carbon material according to the present disclosure, etc., so that the liquid can be alkaline, or the pH value can be increased. In addition, a carboxyl group (obtainable by a nitric acid treatment) or a sulfone group (obtainable by concentrated sulfuric acid) is produced on the surface of the porous carbon material according to the present disclosure, etc., so that the liquid can be acidic or the pH value can be decreased. Alternatively, a reducing agent such as hydrogen can be added to the liquid. When the liquid passes through the microstructure of the porous carbon material according to the present disclosure, etc., the structure (cluster) of the liquid can be changed.

In the fiber composite for the application of a liquid according to the present disclosure, etc., the fibrous member contains the porous carbon material. The specific configurations of the fiber composite for the application of a liquid according to the present disclosure, etc., will be described such as follows. The porous carbon material according to the present disclosure, etc. may be kneaded into the fiber constituting the fibrous member, which is spun and mechanically crimped or crimped by coil crimping, as necessary, to provide a woven or non-woven fabric. There can be provided an item made of this woven or non-woven fabric. The porous carbon material according to the present disclosure, etc. may be attached to the fibrous member using a binder or the like. The porous carbon material according to the present disclosure, etc. may be formed into a desired shape, for example, by using a binder (binding agent) or the like and be inserted between the layered fibrous members. These configurations may be combined, as necessary. Specific products made of the fiber composite for the application of a liquid according to the present disclosure, etc. are, for example, a cosmetic cotton, a cosmetic putting material, a cosmetic puff, a cosmetic cotton wool pad and a sanitizing puff.

Examples of the materials constituting the fibrous member are natural fibers such as cotton, linen, bamboo, wool and pulp; cellulosic regenerated fibers; woven or non-woven fabrics including at least one of synthetic fibers such as polypropylene, polyester, nylon, vinylon, polyethylene, polyamide, aromatic polyamide, polyolefin, polystyrene, acrylic, rayon, polyvinyl alcohol, polytetrafuluoroethylene, an ethylene-vinyl alcohol-based copolymer, polyethylene terephthalate, polypropyrene terephthalate and polybutylene terephthalate; a well-known fabric or fabric-like material obtained by blending these materials, a gauze-like material, and the like. An example of the binder is carboxyl nitrocellulose. The synthetic fibers may have a core-in-sheath type, an eccentric core-in-sheath type, a multilayer bonded type, or a side-by-side structure, etc. and may have a circular cross-section or a modified cross-section.

The porous carbon material according to the present disclosure, etc. can be produced, for example, by carbonizing the plant-based material at 400° C. to 1400° C., and then treating the material with acid or alkali. In the method of producing the porous carbon material according to the present disclosure, etc. (hereinafter simply referred to as “the method of producing the porous carbon material”), the material obtained by carbonizing the plant-based material at 400° C. to 1400° C., which is not yet treated with acid or alkali is referred to as “the porous carbon material precursor” or “the carbonaceous substance”.

In the method of producing the porous carbon material, after the acid or alkali treatment, activation treatment can be performed. Or, after the activation treatment, the acid or alkali treatment may be performed. In the method of producing the porous carbon material including the above-described desirable form, although it depends on the plant-based material being used, the plant-based material may be heated (pre-carbonized) at a temperature lower than the carbonizing temperature (for example, at 400° C. to 700° C.) in an oxygen-free state before the plant-based material is carbonized. As a result of extracting a tar component that would be produced during the carbonization, the tar component can be reduced or removed. The oxygen-free state can be achieved by, for example, providing an inert gas atmosphere including a nitrogen gas or an argon gas, providing a vacuum atmosphere, or almost steaming and baking the plant-based material. In the method of producing the porous carbon material, although it depends on the plant-based material being used, the plant-based material may be immersed into alcohols (for example, methyl alcohol, ethyl alcohol and isopropyl alcohol) in order to decrease mineral components and a water content or to prevent odor generation during the carbonization. Also, in the method of producing the porous carbon material, pre-carbonization may be performed thereafter. The plant-based material that produces a large amount of pyroligneous acid (tar and light crude oil) is an example that is desirably heated under the inert gas atmosphere. Seaweeds, which is the plant-based material containing a large amount of iodine and various minerals, is an example that is desirably pretreated with alcohol.

In the method of producing the porous carbon material, the plant-based material is carbonized at 400° C. to 1400° C. The “carbonization” herein means that organic substances (the plant-based material in the porous carbon material according to the present disclosure, etc.) are typically heated to convert them into carbonaceous substance (for example, see JIS M0104-1984). An example of the atmosphere for carbonization is an oxygen-free atmosphere. Specifically, there are a vacuum atmosphere, an inert gas atmosphere including a nitrogen gas or an argon gas, and an atmosphere where the plant-based material is almost steamed and baked. The rate of temperature increase to the carbonization temperature is not limited, but can be 1° C./min or more, desirably 3° C./min or more, more desirably 5° C./min or more under such atmosphere. The upper limit of the carbonization time may be 10 hours, desirably 7 hours and more desirably 5 hours, but not limited to. The lower limit of the carbonization time may be such that the plant-based material is surely carbonized. The plant-based material may be pulverized to the desired particle size, or classified, as necessary. The plant-based material may be pre-cleaned. Also, the resultant porous carbon material precursor or the porous carbon materials may be pulverized to the desired particle size, or classified, as necessary. In addition, the processed porous carbon material by the activation treatment may be pulverized to the desired particle size, or classified, as necessary. Furthermore, the finally resultant porous carbon material may be sterilized. The furnace used for carbonization is not limited in terms of a shape, a configuration and a structure, and may be a continuous furnace or a batch furnace.

In the method of producing the porous carbon material composite, the porous carbon material is provided by the acid or alkali treatment. Then, to the porous carbon material, a functional material may be attached. After the acid or alkali treatment and before the functional material is attached to the porous carbon material, a process of performing activation treatment may be included. Examples of the functional material are platinum (Pt) or a combination of platinum (Pt) and palladium (Pd). The functional material can be attached to the porous carbon material as fine particles or a thin film, for example. Specifically, the fine particles of the functional material may be attached to the surface (including within pores) of the porous carbon material. Or, the thin film of the functional material may be attached to the surface of the porous carbon material. Or, it may be in sea-island form, in which the functional material, e.g., “island”, is attached to the surface, e.g., “sea” of the porous carbon material. The term “attach” means that different materials are adhered. The functional material can be attached to the porous carbon material by any of the following methods. The porous carbon material may be immersed into the solution containing the functional material to precipitate the functional material onto the surface of the porous carbon material. The functional material may be precipitated onto the surface of the porous carbon material by electroless plating (chemical plating) or a chemical reduction reaction. The porous carbon material may be immersed into the solution containing the precursor of the functional material and heated to precipitate the functional material onto the surface of the porous carbon material. The porous carbon material may be immersed into the solution containing the precursor of the functional material and be exposed to ultrasonic irradiation to precipitate the functional material onto the surface of the porous carbon material. The porous carbon material may be immersed into the solution containing the precursor of the functional material to induce a sol-gel reaction and to precipitate the functional material onto the surface of the porous carbon material.

In the method of producing the porous carbon material, as described above, the activation treatment can increase the numbers of micro pores each having a pore diameter of not greater than 2 nm (which will be described later). Examples of the activation treatment are gas activation and chemical activation. In the gas activation, oxygen, water vapor, carbon dioxide gas, air or the like can be used as an activator. Under the gas atmosphere, the porous carbon material is heated at 700° C. to 1400° C., desirably 700° C. to 1000° C., more desirably 800° C. to 1000° C. for several tens of minutes to several hours, so that the microstructure is grown by the volatile components and carbon molecules in the porous carbon material. More specifically, the heating temperature may be selected based on the types of the plant-based material, the kinds and concentration of the gas and the like, as necessary. In the chemical activation, the porous carbon material is activated by using zinc chloride, iron chloride, calcium phosphate, calcium hydroxide, magnesium carbonate, potassium carbonate, sulfate or the like is used for activation instead of oxygen and water vapor, and is cleaned with hydrochloric acid. The pH of the porous carbon material is adjusted by using an alkaline solution. Then, the porous carbon material is dried.

The surface of the porous carbon material according to the present disclosure, etc. may be chemical treated or molecular modified. For example, as one of the chemical treatments, a nitric acid treatment is performed to produce carboxyl groups on the surface. By the similar treatment as the activation treatment with water vapor, oxygen, alkali or the like, various functional groups such as a hydroxyl group, a carboxyl group, a ketone group or an ester group can be produced on the surface of the porous carbon material. In addition, when the porous carbon material is chemically reacted with chemical species or protein containing a hydroxyl group, a carboxyl group, an amino group or the like, the molecular modification may be possible.

In the method of producing the porous carbon material, silicon components are removed by the acid or alkali treatment from the carbonized plant-based material. The silicon components may be silicon oxides such as silicon dioxide, silicon oxide and a salt of silicon oxide. By removing the silicon components in the carbonized plant-based material, there can be provided the porous carbon material having high specific surface area. In some cases, the silicon components in the carbonized plant-based material may be removed by a dry etching method. In other words, in the desired form of the porous carbon material according to the present disclosure, etc., the plant-based material containing silicon (Si) is used as the raw material, and is converted into the porous carbon material precursor or the carbonaceous substance by carbonizing the plant-based material at high temperature (for example, at 400° C. to 1400° C.). By the carbonization, silicon contained in the plant-based material becomes the silicon components (silicon oxides) such as silicon dioxide (SiO₂), silicon oxide and a salt of silicon oxide, and not silicon carbide (SiC). However, the silicon components (silicon oxides) contained in the plant-based material before the carbonization are not substantially changed even when carbonization is performed at high temperature (for example, at 400° C. to 1400° C.). Therefore, when the acid or alkali (or base) treatment is then performed, the silicon components (silicon oxides) such as silicon dioxide, silicon oxide and a salt of silicon oxide are removed. As a result, there can be provided a high specific surface area value measured by the nitrogen BET method. Furthermore, the desired form of the porous carbon material according to the present disclosure, etc. is an environmentally friendly material derived from natural resources. The microstructure can be provided by treating the silicon components (silicon oxides) originally contained in the raw materials of the plant-based material with acid or alkali, and removing such components. Consequently, the arrangement of the pores maintains the biological order of the plants.

As described above, one of the raw materials of the porous carbon material is the plant-based material. Non-limiting examples of the plant-based material are chaff and straws of rice (paddy), barley, wheat, rye, Japanese millet and foxtail millet; coffee beans, tea leaves (for example, leaves of green tea, black tea and the like); sugar canes (in particular, bagasse); corns (in particular, core of corn); fruit peels (for example, citrus peels such as orange peel, grapefruit peel and mandarin orange peel, banana peel and the like); reeds; Wakame seaweed stems (Undaria pinnatifida); terrestrial vascular plants; ferns; bryophytes; algae; and marine algae. These materials may be used alone, and plural types of such materials may alternatively be used in combination. The shape and the form of the plant-based material are not especially limited. For example, the plant-based material may be chaff or straw itself, or the dried product. In addition, in terms of food processing of beer, liqueur or the like, a residue of various processing including fermentation, roasting, or extracting, can be applied. In particular, from the standpoint of recycling the industrial wastes, it is desirable that chaff and straws after processing, e.g., after threshing, are used. These chaff and straws after processing are easily available in large amounts from, for example, agricultural cooperatives, alcoholic beverage makers, food companies and food processing companies.

The porous carbon material according to the present disclosure, etc. may contain one or more of magnesium (Mg), potassium (K), calcium (Ca), non-metal elements such as phosphorous (P) and sulfur (S), and metal elements such as transition elements. The amount of magnesium (Mg) may be from 0.01% by mass to 3% by mass, the amount of potassium (K) may be from 0.01% by mass to 3% by mass, the amount of calcium (Ca) may be from 0.05% by mass to 3% by mass, the amount of phosphorous (P) may be from 0.01% by mass to 3% by mass, and the amount of sulfur (S) may be from 0.01% by mass to 3% by mass, as examples. In terms of an increase in the specific surface area value, the amounts of these elements are desirably small. It should be appreciated that the porous carbon material may contain elements other than those described above, and the amounts thereof may be changed.

In the present disclosure, various elements can be analyzed by energy dispersive spectrometry (EDS) using an energy dispersive X-ray spectrometer (for example, JED-2200F manufactured by JEOL Ltd.,). The measurement conditions may include, for example, a scanning voltage of 15 kV and an illumination current of 10 μA.

The porous carbon material according to the present disclosure, etc. has many pores. The pores include “mesopores” having a pore diameter in the range from 2 nm to 50 nm, “micropores” having a pore diameter less than 2 nm and “macropores” having a pore diameter exceeding 50 nm. Specifically, the mesopores have many pores having a size of 20 nm or less, especially 10 nm or less, for example. The micropores have many pores having a size of about 1.9 nm, about 1.5 nm and about 0.8 nm to 1 nm, for example. The porous carbon material according to the present disclosure, etc. desirably has a pore volume by the BJH method of 0.2 cm³/g or more, more desirably 0.4 cm³/g or more, and even more desirably 0.6 cm³/g or more.

It is desirable that the porous carbon material according to the present disclosure, etc. desirably has the specific surface area value by the nitrogen BET method (hereinafter may be simply referred to as “the specific surface area value”) of 50 m²/g or more, more desirably 100 m²/g or more, most and even more desirably 400 m²/g or more in order to provide higher functionality.

The nitrogen BET method is to measure the adsorption isotherm by adsorbing and desorbing admolecules, i.e. nitrogen, to/from an adsorbent (herein, the porous carbon material), and analyze the measured data by the BET equation represented by the equation (1). Based on the method, the specific surface area value, the pore volume and the like can be calculated. Specifically, when the specific area surface is calculated on the basis of the nitrogen BET method, the adsorption isotherm is first measured by adsorbing and desorbing the admolecules, i.e., nitrogen, to/from the porous carbon material. Then, [p/{v_(a)(p₀−p)}] is calculated from the measured adsorption isotherm based on the equation (1) or the deformed equation (1′) and is plotted to the relative pressure in equilibrium (p/p₀). The plot is considered as a straight line, and the slope s (=[(C−1)/(C·V_(m))]) and the intercept i (=[1/(C·V_(m))]) are calculated based on least squares method. The V_(m) and C are calculated from the calculated slope s and the intercept i based on the equations (2-1) and (2-2). The specific surface area a_(sBET) is calculated from V_(m) based on the equation (3) (see BELSORP-mini and BELSORP analysis software manual, pp. 62-66, made by BELL Japan Inc.). The nitrogen BET method is the measuring method in accordance with JIS R 1626-1996 “Measuring methods for the specific surface area of fine ceramic powders by gas adsorption using the BET method”.

V _(a)=(V _(m) ·C·p)/[(p−p ₀){1+(C−1)(p/p ₀)}]  (1)

[p/{V _(a)(p ₀ −p)}]=[(C−1)/(C·V _(m))](p/p ₀)+[1/(C·V _(m))]  (1′)

V _(m)=1/(s+i)  (2-1)

C=(s/i)+1  (2-2)

a _(sBET)+(V _(m) ·L·σ)/22414  (3)

where,

-   -   V_(a): Adsorbed amount     -   V_(m): Adsorbed amount of monolayer     -   p: Nitrogen pressure in equilibrium     -   p₀: Saturated vapor pressure of nitrogen     -   L: The Avogadro number     -   σ: Adsorbed section area of nitrogen

When the pore volume V_(p) is calculated by the nitrogen BET method, the adsorption data of the measured adsorption isotherm is, for example, linearly interpolated to determine the adsorbed amount Vat relative pressure set for calculating the pore volume. The pore volume V_(p) can be calculated from the adsorbed amount V based on the equation (4) (see BELSORP-mini and BELSORP analysis software manual, pp. 62-66, made by BELL Japan Inc.). The pore volume determined by the nitrogen BET method may be referred to simply as “the pore volume”.

V _(p)=(V/22414)×(M _(g)/ρ_(g))  (4)

where,

-   -   V: Adsorbed amount at relative pressure     -   M_(g): Molecular weight of nitrogen     -   ρ₉: Density of nitrogen

The pore diameter of the mesopores can be calculated as, for example, the pore distribution from the change rate of the pore volume to the pore diameter based on the BJH method. The BJH method is widely used as a method for pore diameter distribution analysis. When the pore diameter distribution is analyzed by the BJH method, the adsorption isotherm is first measured by adsorbing and desorbing the admolecules, i.e., nitrogen, to/from the porous carbon material. Then, based on the measured adsorption isotherm, the thickness of the adsorbed layer is determined when the adsorbed molecules (for example, nitrogen) that fill the pores are gradually adsorbed/desorbed, and the inner diameter (twice the length of core diameter) of the pores is determined. Based on the equation (5), the pore radius r_(p) is calculated. Based on the equation (6), the pore volume is calculated. Then, the pore distribution curve is obtained by plotting the change rate of the pore volume (dV_(p)/dr_(p)) to the pore diameter (2r_(p)) based on the pore radius and the pore volume (see BELSORP-mini and BELSORP analysis software manual, pp. 85-88, made by BELL Japan Inc.).

r _(p) =t+r _(k)  (5)

V _(pn) =R _(n) ·dV _(n) −R _(n) ·dt _(n) c·ΣA _(pj)  (6)

where,

R _(n) =r _(pn) ²/(r _(kn)−1+dt _(n))²  (7)

where,

-   -   r_(p): Pore radius     -   r_(k): Core radius (inner diameter/2) when the adsorbed layer         having a thickness of t is adsorbed on the inner wall of the         pore having the pore radius r_(p) at the pressure     -   V_(pn): Pore volume at the time of n-th adsorption/desorption of         nitrogen     -   dV_(n): Amount of change at the time of n-th         adsorption/desorption of nitrogen     -   dt_(n): Amount of change in the thickness t_(n) at the time of         n-th adsorption/desorption of nitrogen     -   r_(kn): Core radius at the time of n-th adsorption/desorption of         nitrogen     -   c: Fixed value     -   r_(pn): Pore radius at the time of n-th adsorption/desorption of         nitrogen

In addition, ΣA_(pj) represents the integration value of the areas of the pore walls from j=1 to j=n−1.

The pore diameter of the micropores can be calculated as, for example, the pore distribution from the change rate of the pore volume to the pore diameter based on the MP method. When the pore distribution is analyzed by the MP method, the adsorption isotherm is first measured by adsorbing nitrogen to the porous carbon material. Then, the adsorption isotherm is converted (t plotted) into the pore volume to the thickness t of the adsorbed layer. The pore distribution curve is obtained based on curvature (amount of change in the pore volume to amount of change in the thickness t_(n) of the adsorbed layer) of the plot (see BELSORP-mini and BELSORP analysis software manual, pp. 72-73, 82, made by BELL Japan Inc.).

The Non Localized Density Functional Theory (NLDFT) method specified in JIS Z8831-2:2010 “Pore Size Distribution and Porosity of Powders (Solid Materials)—Part 2: Method of Measuring Mesopores and Macropores using Gas Absorption” and JIS Z8831-3:2010 “Pore Size Distribution and Porosity of Powders (Solid Materials)—Part 3: Method of Measuring Micropores using Gas Absorption” employs a program accompanying the automatic specific surface area/pore distribution measuring apparatus “BELSORP-MAX” manufactured by BELL JAPAN, INC. as an analyzing program. An analysis is carried out using a model having a cylindrical shape and assuming carbon black (CB), as prerequisites for the analysis. Then, a distribution function for pore distribution parameters is set as “no-assumption”, and smoothing will be performed ten times on distribution data thus obtained.

The porous carbon material precursor is treated with an acid or alkali. For example, the porous carbon material precursor may be immersed into a water solution of an acid or alkali. Or, the porous carbon material precursor may be reacted with an acid or alkali in the vapor phase. More specifically, the acid treatment may be carried out using an acidic fluorine compound as an acid such as a hydrogen fluoride, hydrofluoric acid, ammonium fluoride, calcium fluoride, or sodium fluoride. When a fluorine compound is used, the amount of fluorine is desirably four times the amount of silicon in silicon components included in the porous carbon material precursor, and a water solution of the fluorine compound desirably has a concentration of 10 wt % or more. When silicon components (e.g., silicon dioxide) included in the porous carbon material precursor are removed by the use of a hydrofluoric acid, silicon dioxide reacts with the hydrofluoric acid as indicated by formula (A) or (B), and silicon can be eliminated as hydrogen hexafluorosilicate (H₂SiF₆) or silicon tetrafluoride (SiF₄). Thus, a porous carbon material is obtained. The material may thereafter be washed and dried.

SiO₂+6HF→H₂SiF₆+2H₂O  (A)

SiO₂+4HF→SiF₄+2H₂O  (B)

When the precursor is treated with alkali (base), the alkali may be sodium hydroxide. When a water solution of alkali is used, the pH of the water solution may be 11 or more. When silicon components (e.g., silicon dioxide) included in the porous carbon material precursor are removed by the use of a water solution of sodium hydroxide, silicon dioxide is made to react as indicated by formula (C) by the heating of the water solution of sodium hydroxide. The silicon can be eliminated as sodium silicate (Na₂SiO₃) resulting from the reaction. Thus, a porous carbon material is obtained. When the precursor is treated by the reaction caused by sodium hydroxide in the vapor phase, sodium hydroxide in a solid state is heated to cause it to react as indicated by formula (C). The silicon can be eliminated as sodium silicate (Na₂SiO₃) resulting from the reaction. Thus, a porous carbon material is obtained. The material may thereafter be washed and dried.

SiO₂+2NaOH→Na₂SiO₃+H₂O  (C)

The porous carbon material according to the present disclosure may be a porous carbon material including holes having three-dimensional regularity, for example, as disclosed in Japanese Unexamined Patent Application Publication No. 2010-106007 (a porous carbon material having what is called an inverse opal structure). Specifically, the porous carbon material has spherical holes in a three dimensional arrangement having an average diameter in the range from 1×10⁻⁹ m to 1×10⁻⁵ m and having a surface area of 3×10² m²/g or more. Desirably, the holes are arranged in a disposition similar to a crystalline structure in a macroscopic point of view. Alternatively, the porous carbon material has holes arranged on a surface thereof in a disposition similar to the alignment of a (111) plane of a face-centered cubic structure in a macroscopic point of view.

EXAMPLE 1

Example 1 of the present disclosure is related to a fiber composite for the application of a liquid according to the first to third embodiments of the present disclosure.

As expressed in accordance with the first embodiment of the present disclosure, Example 1 of the present disclosure is the fiber composite for the application of a liquid, including a fibrous member containing a porous carbon material having a specific surface area value by the nitrogen BET method of 10 m²/g or more, and a pore volume of 0.2 cm³/g or more, desirably 0.4 cm³/g or more, more desirably 0.6 cm³/g or more. As expressed in accordance with the second embodiment of the present disclosure, Example 1 includes a fibrous member containing a porous carbon material having a specific surface area value by the nitrogen BET method of 10 m²/g or more, and a total pore volume (simply referred to as “volume A”) by the Non Localized Density Functional Theory of 0.5 cm³/g or more, desirably 1.0 cm³/g or more, wherein the pore has a diameter in the range from 1×10⁻⁹ m to 5×10⁻⁷ m. As expressed in accordance with the third embodiment of the present disclosure, Example 1 includes a fibrous member containing a porous carbon material having a specific surface area value by the nitrogen BET method of 10 m²/g or more, and at least one peak in a pore diameter distribution by the Non Localized Density Functional Theory in the range from 3 nm to 20 nm, in which the ratio of volume of the pores each having a pore diameter in the range from 3 nm to 20 nm is 0.2 or more, desirably 0.4 or more, of the total pore volume (corresponds to volume A).

In Example 1, the fiber component for the application of a liquid is formed as a cosmetic cotton. The fibrous member is composed of a non-woven fabric including cotton, and has a rectangular planar shape. Specifically, the fibrous member is kneaded into the fiber (cotton) in advance, and then spun to provide the non-woven fabric based on the well-known method. Thus, the fiber component for the application of a liquid of Example 1 can be obtained.

In Example 1, the fibrous member is impregnated with the liquid so as to apply the liquid to an object. More specifically, the fibrous member is impregnated with the liquid of well-known skin lotion, and is contacted with to user's skin including a face, arms, and limbs to make the liquid (skin lotion) apply or attach to them. When the liquid (skin lotion) is contacted with the porous carbon material, the oxidative stress substances contained in the liquid (skin lotion) are removed. Also, when the liquid (skin lotion) is contacted with the porous carbon material, the oxidation-reduction potential of the liquid (skin lotion) is decreased. In other words, the properties such as antioxidative properties are added to the liquid (skin lotion).

The plant-based material which is the raw material of the porous carbon material is rice (paddy) chaff Example 1. The porous carbon material of Example 1 is obtained by carbonizing chuff to convert it into a carbonaceous substance (porous carbon material precursor) and thereafter treating the substance with an acid. A method of manufacturing the porous carbon material of Example 1 will be described below.

In the process of manufacturing the porous carbon material in the Example 1, the plant-based material (silicon content of about 20% by mass) was carbonized at a temperature in the range from 400° C. to 1400° C., and was thereafter treated with an acid or alkali, so that the porous carbon material would be obtained. First, a heating process (a preliminary carbonizing process) was performed on chaff under inert gas. Specifically, the chaff was carbonized by the heating at 500° C. for 5 hours in a flow of nitrogen gas, and a carbide was obtained. Such a process makes it possible to reduce or eliminate tar components which will otherwise be generated at a subsequent carbonizing step. Thereafter, 10 grams of the carbide was put in a crucible made of alumina, and the temperature of the carbide was raised to 800° C. at a rate of 5° C./min in a flow of nitrogen gas (10 liters/min). The carbide was carbonized at 800° C. for one hour and converted into a carbonaceous substance (porous carbon material precursor), and the substance was cooled down to room temperature. The nitrogen gas was kept flowing during the carbonization and cooling. Next, the porous carbon material precursor was acid-treated by immersion in a water solution of hydrofluoric acid of 46 vol % overnight, and the precursor was washed with water and ethyl alcohol until it reached a pH of 7. Next, the precursor was dried at 120° C. and was activated by heating at 900° C. for 3 hours in a flow of water vapor (5 liters/min). The porous carbon material (silicon content of about 0.5% by mass) of Example 1 was obtained.

As Comparative Example 1, active carbon manufactured by Wako Pure Chemical Industries, Ltd. was used.

A nitrogen absorption/desorption test was carried out to find the specific surface areas and the pore volumes, using a measuring apparatus BELSORP-mini (manufactured by BELL JAPAN, INC.). The measurement was carried out at a measurement relative pressure in equilibrium (p/p₀) of 0.01 to 0.99. The specific surface areas and the pore volumes were calculated using a BELSORP analysis program. Pore diameter distributions of mesopores and micropores were obtained by conducting a nitrogen absorption/desorption test using the above-mentioned measuring apparatus and carrying out calculations using the BELSORP analysis program based on the BJH method and the MP method. The pore distribution of the porous carbon material was measured by mercury intrusion method. Specifically, a mercury porosimeter (PASCAL440 manufactured by Thermo Fisher Scientific Inc.) was used to conduct the mercury intrusion method. The measurement range of the pores was 10 μm to 2 nm. Further, the measurement based on the Non Localized Density Functional Theory (NLDFT) was carried out using an automatic specific surface area/pore distribution measuring apparatus “BELSORP-MAX” manufactured by BELL JAPAN, INC. Prior to the measurement, the samples were subjected to drying at 200° C. for 3 hours as a pre-process.

The specific surface area and the pore volume of each of the porous carbon material of Example 1, a porous material composite of Example 2 described later, and the active carbon of Comparative Example 1 was measured. Table 1 shows the results. In Table 1, the term “specific surface area” means a specific surface area in m²/g obtained according to the nitrogen BET method. The terms “MP method”, “BJH method” and “mercury intrusion method” refer to a pore (micropore) volume result measured by the MP method, a pore (mesopore to macropore) volume result measured by the BJH method, and a pore volume result measured by the mercury intrusion method, respectively. The units are in cm³/g. Table 2 shows the results of the measurement by the NLDFT method. The total pore volume corresponds to the value of the volume A.

TABLE 1 Specific Mercury surface BJH MP intrusion area method method method Example 1 1700 1.08 0.60 4.14 Example 2 1286 0.65 0.50 Comparative 982 0.08 0.38 1.10 Example 1

TABLE 2 Volume Total volume of all percentage pores (volume A) Example 1 0.479 1.33 cm³/g Example 2 0.432 1.38 cm³/g Comparative 0.125 0.40 cm³/g Example 1

A removal amount of hydroxyl radicals (OH.) in water of each of the following, a porous carbon material of Example 1, a porous material composite of Example 2 and the active carbon of Comparative Example 1, was measured by an electron spin resonance (ESR) device. Specifically, 15 mg of the sample was added to 50 ml of hydroxyl radical producing solution, and was agitated. The solution was measured by the ESR. As a result, the relative removal amount of the hydroxyl radicals of Example 1 was 3.2, and that of Example 2 described later was 7.4, when that of Comparative Example 1 was considered as 1.

The pH of water and the oxidation reduction potential of each of the porous carbon material of Example 1, a porous material composite of Example 2 described later, and the active carbon of Comparative Example 1 were measured. Table 3 shows the results. For reference, Table 3 also shows the results of the oxidation reduction potentials of tap water etc.

TABLE 3 pH before addition pH after addition Example 1 7.1 9.3 Comparative 7.1 6.4 Example 1 Oxidation Oxidation reduction reduction potential before potential after addition addition Example 1 333 mV 142 mV Comparative 333 mV 297 mV Example 1 Oxidation reduction potential Tap water 547 mV Distilled water 333 mV Commercially 321 mV available natural water A Commercially 258 mV available natural water B

FIG. 1 is a graph showing the relation between the adding amount of the porous carbon material according to Example 1/active carbon according to Comparative Example 1 and the pH. FIG. 2 is a graph showing the relation between the adding amount of the porous carbon material according to Example 1/active carbon according to Comparative Example 1 and the oxidation-reduction potential. The oxidation-reduction potential and the pH of water were measured by adding 300 mg, 150 mg, 70 mg, 30 mg or 10 mg of the sample to 20 ml of distilled water. Each sample solution was agitated for 1 minute, and then filtrated.

In Example 1, the pH of water after the porous carbon material was added was increased, and the oxidation-reduction potential after the addition was significantly lowered, as compared with those of Comparative Example 1. As described above, the relative removal amount of the hydroxyl radicals was 3.2. It was revealed that hydroxyl radicals could be removed at high efficiency.

EXAMPLE 2

Example 2 is alternative of Example 1 and is related to a porous carbon material composite. In Example 2, as the functional material, a metal-based material (specifically, platinum micropowder, platinum nanoparticles) attached to a porous carbon material was used. The porous carbon material was produced by the similar method described in Example 1.

Specifically, in Example 2, 8 ml of a 5 mmol H₂PtC₁₆ solution and 3.5 mg of L-ascorbic acid (surface protector) were added to 182 ml of distilled water, and were agitated for a while. Thereafter, 0.43 g of the porous carbon material described in Example 1 was added thereto, which was irradiated with ultrasonic waves for 20 minutes, and 10 ml of 40 mmol NaBH₄ solution was added thereto, and then was agitated for 3 hours. Then, suction filtration and drying at 120° C. were performed to provide a black powder sample, i.e., the porous carbon material composite of Example 2. A cosmetic cotton made of the fiber composite for the application of a liquid was produced by the similar method as described in Example 1.

Also in Example 2, the fibrous member is impregnated with the liquid so as to apply the liquid to an object. More specifically, the fibrous member is impregnated with the liquid of well-known skin lotion, and is contacted with to user's skin including a face, arms, and limbs to make the liquid (skin lotion) apply or attach to them. When the liquid (skin lotion) is contacted with the porous carbon material, the oxidative stress substances contained in the liquid (skin lotion) are removed. Also, when the liquid (skin lotion) is contacted with the porous carbon material, the oxidation-reduction potential of the liquid (skin lotion) is decreased. In other words, the properties such as antioxidative properties are added to the liquid (skin lotion).

In Example 2, as described above, the relative removal amount of the hydroxyl radicals was 7.4. It was revealed that hydroxyl radicals could be removed at higher efficiency than in Example 1.

The present disclosure has been described based on the embodiment thereof, and the present disclosure is not limited to the embodiments and may be modified in various ways. While the chaff is used as the raw material of the porous carbon material is made from rice chaff in Examples, other plants may be used. For example, other usable plants include straws, reeds, stems of Wakame seaweed, terrestrial vascular plants, ferns, bryophytes, algae, and marine algae. Those plants may be used alone, and plural types of such plants may alternatively be used in combination. Specifically, chaff of paddy (e.g., Isehikari produced in Kagoshima prefecture in Japan) may be the plant-based material which is the raw material of the porous carbon material. The chaff may be carbonized into a carbonaceous substance (a porous carbon material precursor), and the carbonaceous substance may be treated with an acid to obtain the porous carbon material. Alternatively, gramineous reeds may be the plant-based material is the raw material of the porous carbon material. The gramineous reeds may be carbonized into a carbonaceous substance (a porous carbon material precursor), and the carbonaceous substance may be treated with an acid to obtain the porous carbon material. Advantages similar to those described above were achieved by the porous carbon material obtained by treating a material using alkali (base) such as a water solution of sodium hydroxide instead of a water solution of hydrofluoric acid. The method of producing the porous carbon material or the porous carbon material composite can be similar to that in Examples 1 and 2.

Alternatively, stems of Wakame seaweed (cropped in Sanriku, Iwate prefecture in Japan) may be the plant-based material which is the raw material of the porous carbon material. The stems of Wakame seaweed may be carbonized into a carbonaceous substance (porous carbon material precursor), and the carbonaceous substance may be treated with an acid to obtain the porous carbon material. Specifically, the stems of Wakame seaweed are heated at a temperature of, for example, 500° C. and carbonized. The stems of Wakame seaweed may be treated with alcohol before the heating. Specifically, the raw material may be immersed in ethyl alcohol or the like. As a result, moisture included in the raw material is reduced, and the process also allows elution of elements other than carbon and mineral components which will otherwise be included in the porous carbon material finally obtained. The treatment with alcohol suppresses the generation of gasses during the carbonizing process. More specifically, stems of Wakame seaweed are immersed in ethyl alcohol for 48 hours. It is desirable to perform an ultrasonic process on the material in ethyl alcohol. The stems of Wakame seaweed are then carbonized by being heated at 500° C. for 5 hours in a flow of nitrogen gas to obtain a carbide. Such a process (preliminary carbonizing process) can reduce or eliminate tar components which will otherwise be generated at the subsequent carbonizing step. Thereafter, 10 grams of the carbide is put in a crucible made of alumina, and the temperature of the carbide is raised to 1000° C. at a rate of 5° C./min. in a flow of nitrogen gas (10 liters/min). The carbide is carbonized at 1000° C. for 5 hours and converted into a carbonaceous substance (porous carbon material precursor), and the substance is cooled down to room temperature. The nitrogen gas is kept flowing during the carbonization and cooling. Next, the porous carbon material precursor is acid-treated by immersion in a water solution of hydrofluoric acid of 46 vol % overnight, and the precursor is washed with water and ethyl alcohol until it reaches a pH of 7. Finally, the precursor is dried so that a porous carbon material will be obtained.

When the plant containing at least one selected from the group consisting of sodium, magnesium, potassium and calcium (specifically, for example, citrus peel such as mandarin orange peel, orange peel and grapefruit peel and banana peel), is used as the raw material of the porous carbon material, the porous carbon material allows elution of a large amount of mineral components to water, and even may control the hardness of water. In this case, it is desirable that the total amount of sodium (Na), magnesium (Mg), potassium (K) or calcium (Ca) included is from 0.4% by mass or more.

The present disclosure may have the following configurations.

[1] <<A Fiber Composite for the Application of a Liquid: First Embodiment>>

A fiber composite for the application of a liquid, including a fibrous member containing a porous carbon material having a specific surface area value as measured by the nitrogen BET method of 10 m²/g or more, and a pore volume as measured by the BJH method of 0.2 cm³/g or more, desirably 0.4 cm³/g or more.

[2] <<A Fiber Composite for the Application of a Liquid: Second Embodiment>>

A fiber composite for the application of a liquid, including a fibrous member containing a porous carbon material having a specific surface area value as measured by the nitrogen BET method of 10 m²/g or more, and a total pore volume determined by the Non Localized Density Functional Theory of 0.5 cm³/g or more, desirably 1.0 cm³/g or more, of which the pores have diameters in the range from 1×10⁻⁹ m to 5×10⁻⁷ m.

[3] <<A Fiber Composite for the Application of a Liquid: Third Embodiment>>

A fiber composite for the application of a liquid, including a fibrous member containing a porous carbon material having a specific surface area value as measured by the nitrogen BET method of 10 m²/g or more, an at least one peak in a pore diameter distribution determined by the Non Localized Density Functional Theory in the range from 3 nm to 20 nm, and a ratio of the total volume of the pores with diameters in the range from 3 nm to 20 nm, being 0.2 or more of the total pore volume.

[4] The fiber composite for the application of a liquid according to any one of [1] to [3] above, in which a functional material is attached to the porous carbon material.

[5] The fiber composite for the application of a liquid according to any one of [1] to [4] above, in which

the fibrous member is configured to be impregnated with the liquid so that the liquid is to be applied.

[6] The fiber composite for the application of a liquid according to [5] above, in which

the porous carbon material is configured to contact with the liquid so that oxidative stress substances contained in the liquid are removed.

[7] The fiber composite for the application of a liquid according to [5] above, in which

the liquid is contacted with the porous carbon material so that the oxidation-reduction potential of the liquid is decreased.

[8] The fiber composite for the application of a liquid according to any one of [1] to [7] above, in which

one of the raw materials in the porous carbon material is a plant-based material containing silicon.

[9] The fiber composite for the application of a liquid According to [8] above, in which

the silicon content is 1% by mass or less.

Embodiments and examples of the present disclosure have been described, but the technology is not limited to those described above in the embodiments and examples, and various modifications are possible within the technological scope of the present technology.

For example, the numerical values, structures, configurations, shapes and materials described above in embodiments and examples are nothing but examples and numerical values, structures, configurations, shapes, materials and others different from them may be used, as necessary.

The present disclosure contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2011-130967 filed in the Japan Patent Office on Jun. 13, 2011, the entire content of which is hereby incorporated by reference.

It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof. 

1. A fiber composite for the application of a liquid, comprising a fibrous member containing a porous carbon material having a specific surface area value as measured by the nitrogen BET method of 10 m²/g or more, and a pore volume as measured by the BJH method of 0.2 cm³/g or more.
 2. A fiber composite for the application of a liquid, comprising a fibrous member containing a porous carbon material having a specific surface area value as measured by the nitrogen BET method of 10 m²/g or more, and a total pore volume determined by the Non Localized Density Functional Theory of 0.5 cm³/g or more, of which pores have diameters in the range from 1×10⁻⁹ m to 5×10⁻⁷ m.
 3. A fiber composite for the application of a liquid, comprising a fibrous member containing a porous carbon material having a specific surface area value as measured by the nitrogen BET method of 10 m²/g or more, an at least one peak in a pore diameter distribution determined by the Non Localized Density Functional Theory in the range from 3 nm to 20 nm, and a ratio of the total volume of the pores with diameters in the range from 3 nm to 20 nm, being 0.2 or more of the total pore volume.
 4. The fiber composite for the application of a liquid, according to claim 1, wherein a functional material is attached to the porous carbon material.
 5. The fiber composite for the application of a liquid according to claim 1, wherein the fibrous member is configured to be impregnated with the liquid so that the liquid is to be applied.
 6. The fiber composite for the application of a liquid according to claim 5, wherein the porous carbon material is configured to contact with the liquid so that oxidative stress substances contained in the liquid are removed.
 7. The fiber composite for the application of a liquid according to claim 5, wherein the porous carbon material is configured to contact with the liquid so that the oxidation-reduction potential of the liquid is decreased.
 8. The fiber composite for the application of a liquid according to claim 1, wherein one of the raw materials in the porous carbon material is a plant-based material containing silicon.
 9. The fiber composite for the application of a liquid according to claim 8, wherein the silicon content is 1% by mass or less. 